Serious public health consequences could result from pathogen resistance to common disinfectants used in drinking water treatment, especially when potable water is reused. The reuse of potable water with frequent disinfection may encourage the emergence of resistance. This study looked at how Escherichia coli developed resistance to repeated monochloramine and ferrate disinfections. After 12 or more treatment rounds, E. coli cultures repeatedly exposed to monochloramine developed resistance, whereas repeated ferrate disinfection did not. Initial rounds of disinfection with monochloramine caused cells to become Viable But Nonculturable (VBNC); however, further monochloramine treatments increased culturability, which coincided with a reduction in the percentage of VBNC cells after disinfection. monochloramine. The development of monochloramine resistance was significantly influenced less by the frequency of treatment and more by the total number of disinfection episodes (12 times). The evolved monochloramine-stressed cultures were successfully inactivated (>3-log10) by ferrate in addition to preventing resistance, indicating that the evolutionary adaptations against monochloramine were unsuccessful against ferrate. Ferrate is a promising disinfectant that warrants more investigation due to the absence of resistance to it. The results of this study show that bacterial resistance development can be influenced by the frequency of disinfection as well as the type of disinfectant used. Therefore, ongoing monitoring is required to assess the resistance profile of harmful bacteria in order to evaluate present and future water disinfection strategies, particularly within potable water reuse.
